Sodium sulphite

Specific investigations: other studies

Administrative data

Endpoint:

specific investigations: other studies

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

other: not rated

Rationale for reliability incl. deficiencies:

other: In vitro study on effects of sodium sulfite on human neutrophils.

Data source

Reference

Reference Type:

publication

Title:

Functional responses of human neutrophils to sodium sulfite (Na2SO3) in vitro.

Author:

Labbé, P.; et al.

Year:

1998

Bibliographic source:

Human and Experimental Toxicolotgy, 17, 600-605

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study focuses on the in vitro interactions of sodium sulfite (Na2SO3) with human neutrophils. The neutrophil suspension was isolated from the blood of healthy volunteers. It was used in concentrations of 0.1, 1 or 10 mM.

GLP compliance:

no

Type of method:

in vitro

Endpoint addressed:

immunotoxicity

Test material

Test material information

Constituent 1

Reference substance name:

Sodium sulphite

EC Number:

231-821-4

EC Name:

Sodium sulphite

Cas Number:

7757-83-7

Molecular formula:

NA2SO3

IUPAC Name:

disodium sulfate

Details on test material:

- Name of test material (as cited in study report): sodium sulfite
- Physical state: solid

Results and discussion

Details on results:

Na2SO3 was not toxic to cells at 0.1, 1.0, or 10 mM (as assessed by Trypan blue exclusion.

Sodium sulfite induces superoxide production by itself and primes the response to fMLP:
- superoxide producton by neutriphils is increased by Na2SO3 in a concentration dependent fashion: after 5min, superoxide production from human neutrophils stimulated with buffer, 0.1, 1.0, 10 mM Na2SO3, or 10E-7 MPMA was 2.6±0.5 (mean±s.e.m., n=3); 4.5±1.3: 9.5±1.1; 22.3±2.1 and 24±4.0 mmoles/10E6 cells, respectively
- results were 3.3±0.1; 5.8±0.3; 14.0±0.1; 34.9±0.6 and 41.8±0.9 after 30 min of stimulation, in the same order
- Na2SO3 can also prime human neutrophils to respond to fMLP in a concentration-dependent fashion: after 30 min of incubation with buffer, 0.1, 1.0, 10 mM Na2SO3, or GM-CSF (positive control), superoxide production by fMLP-induced neutrophils (5 min) was 11.5±2.1; 14.5±2.1; 38.4±1.6 or 22.0±1.9 nmoles/10E6 cells

Na2SO3 induces RNA synthesis in a concentration-dependent fashion but does not induce cell shape changes:
- total RNA synthesis increased in a concentration dependent manner as assessed by incorporation of 5-[3H]uridine
- because of variability among individuals, results are expressed as stimulation indices and an index >1 indicates stimulation
- indices of stimulation were 1.01±0.08 (mean±s.e.m., n=8); 1.20±0.2; and 1.50±0.3 for 0.1, 1.0, or 10 mM Na2SO3, respectively and 4.93±0.7 for GM-CSF
- Na2SO3 did not induce neutrophil shape changes as the cells remained with a round morphology in contrast to the irregular morphology observed with GM-CSF

Na2SO3 does not modulate neutrophil apoptosis rate:
- neutrophil apoptosis rates remain similar to control cells (34.3±4.6 % of cells in apoptosis, mean ± s.e.m.) when incubated with 0.1 (41.5±9.3 %), 1.0 (33.2±5.3 %), or 10 mMNa2SO3 (44.7±6.1 %) in contrast to GM-CSF which, as expected, significantly delays neutrophil apoptosis (11.7±2.4 %)
- during co-incubation with GM-CSF, Na2SO3 did not reverse the known delaying effect of GM-CSF since the number of apoptotic cells was stable ranging from 15 to 17 %

Applicant's summary and conclusion

Conclusions:

The present study indicates that human neutrophils can be activated by Na2SO3. In particular, this sulfite strongly induces superoxide production by itself as well as it can prime neutrophils to respond to fMLP.